<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    let day = prompt('请输入一个星期数：')
    switch (day) {
      case '星期一':
        alert('Monday')
        break
      case '星期二':
        alert('Tuesday')
        break
      case '星期三':
        alert('Wensday')
        break
      case '星期四':
        alert('Thursday')
        break
      case '星期五':
        alert('Friday')
        break
      case '星期六':
        alert('Saturday')
        break
      case '星期日':
        alert('Sunday')
        break
    }
  </script>
</body>
</html>